Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
  • B41C1/00—Forme preparation
  • B41C1/02—Engraving; Heads therefor
  • B41C1/04—Engraving; Heads therefor using heads controlled by an electric information signal
  • B41C1/045—Mechanical engraving heads
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T82/00—Turning
  • Y10T82/12—Radially moving rotating tool inside bore
  • Y10T82/125—Tool simultaneously moving axially
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T82/00—Turning
  • Y10T82/12—Radially moving rotating tool inside bore
  • Y10T82/125—Tool simultaneously moving axially
  • Y10T82/128—Pivoted to tool-carrier

Definitions

• the invention relates to the field of electronic reproduction technology and relates to an engraving member of an electronic engraving machine for engraving printing cylinders for gravure printing.
• an engraving element with an engraving stylus as a cutting tool moves in the axial direction along a rotating printing cylinder.
• the engraving stylus which is controlled by an engraving control signal, cuts wells arranged in engraving lines in an engraving grid into the outer surface of the printing cylinder.
• the engraving control signal is formed by superimposing a periodic raster signal with image signal values which represent the tonal values to be reproduced between "black” and "white".
• the screen signal causes the engraving stylus to vibrate in the direction of the printing cylinder, the image signal values determining the engraving depths of the cells in accordance with the tone values to be reproduced.
• the electromagnetic drive element consists of a stationary electromagnet to which the engraving control signal is applied, in the air gap of which the armature of a rotating system moves.
• the rotating system consists of a shaft, the armature, a bearing for the shaft and a damping device. One shaft end merges into a resilient torsion bar that is clamped in place, while the other shaft end carries a lever to which the engraving stylus is attached.
• the engraving stylus is often a prismatic cut diamond, which is attached with its shaft to the lever of the engraving element.
• the engraving stylus essentially consists of a front rake face with respect to the engraving direction and an oblique rear open face facing away from the rake face.
• the intersection lines between the rake face and the free face form the cutting tip of the engraving stylus.
• the angle between the sloping free surface and the tangential plane at the point of contact between the cutting tip and the lateral surface of the printing cylinder is referred to as the clearance angle.
• the clearance angle of the engraving stylus limits the steepness with which the engraving stylus can penetrate the printing cylinder without the free surface touching the wall of the cups.
• wells that are compressed in the direction of the engraving line are engraved with a steep wall and elongated wells are engraved with a flat wall.
• the free surface of the engraving stylus touches the wall of the cells and the cutting process is interrupted. The result is that the engraving depths required for engraving with the correct tonal value are not reached and cups with an undesirable asymmetrical shape are engraved.
• the invention is based on the object of improving an engraving element of an electronic engraving machine for engraving printing forms in such a way that engraving with the correct tone value is achieved in particular even with upset cells.
• Fig. 1 shows the basic structure of an engraving element
• Fig. 2 shows an engraving stylus and an impression cylinder (in sections) in cross section.
• FIG. 1 shows a perspective illustration of the structure of an engraving element, which in principle has a drive system, in the example shown an electromagnetic drive system, and a rotary system.
• the electromagnetic drive element consists of a stationary electromagnet (1) with two opposing u-shaped laminated cores (2) and two air gaps (3) between the legs of the laminated cores (2).
• a coil (5) In the recesses (4) of the laminated core (2) of the electromagnet (1) there is a coil (5), of which only one side of the coil is shown. An engraving control signal flows through the coil (5).
• the rotating system consists of a shaft (6), an armature (7) attached to the shaft (6), and a damping device (8) and a bearing (9) for the shaft (6).
• the armature (7) can be moved in the air gaps (3) of the electromagnet (1).
• One end of the shaft merges into a resilient torsion bar (10) which is clamped in a fixed support (11, 12).
• the other shaft end (13) carries a lever (14) on which an engraving stylus (15) is attached, for example in the form of a diamond.
• the damping device (8) and the bearing (9) are arranged between the armature (7) and the lever (14) with the engraving stylus (15).
• the magnetic field generated in the air gaps (2) of the electromagnet (1) exerts an electrical torque on the armature (7) of the shaft (6), which counteracts the mechanical torque of the torsion bar (10).
• the electrical torque rotates the shaft (6) about its longitudinal axis with one of the respective current engraving control signal value proportional angle of rotation from a rest position, and the torsion bar (10) brings the shaft (6) back to the rest position.
• the rotation of the shaft (6) causes the engraving stylus (15) to perform a lifting movement in the direction of the lateral surface of a printing cylinder, not shown, which determines the depth of penetration of the engraving stylus (15) into the printing cylinder.
• the drive system for the engraving stylus (15) can also be designed as a solid-state actuator element, which consists, for example, of a piezoelectric or a magnetostrictive material.
• Fig. 2 shows a cross section through the engraving stylus and a pressure cylinder.
• a radial partial cross section through a pressure cylinder (16) is shown in the area of its lateral surface (17).
• the engraving stylus (15) which is designed as a prismatic cut diamond, is also shown in cross section.
• the rotating printing cylinder (16) may move in the direction of an arrow (18) under the engraving stylus (15), an arrow (19) indicating the direction of engraving for the cups (20) on a circumferential engraving line on the lateral surface (17) of the printing cylinder (16) indicates.
• the engraving stylus (15) essentially consists of a shaft (21), a rake face (22) which is at the front with respect to the engraving direction (19) and a free face (23) facing away from the rake face (22).
• the cutting lines between the rake surface (22) and the free surface (23) form the cutting tip (24) of the engraving stylus (15).
• the free surface (23) encloses the clearance angle ( ⁇ ) with a tangential surface in the point of contact of the cutting tip (24) and the outer surface (17) of the pressure cylinder (16).
• the engraving element is aligned with the lateral surface (17) of the printing cylinder (16) in such a way that the engraving stylus (15) for engraving the cups (20) has a stroke movement, indicated by a double arrow (25), in the direction of the printing cylinder (16) and in Opposite direction.
• the clearance angle ( ⁇ ) of the engraving stylus (15) is increased according to the invention in that the engraving stylus (15) in the engraving direction (19) relative to one each radially to the printing cylinder (16), ie perpendicularly is arranged inclined to the lateral surface (17), extending reference straight line (26).
• the angle of inclination ( ⁇ ), which the inclined engraving stylus (15) includes with the reference straight line (26), is expediently chosen to be 1 ° to 5 °, preferably 3 °.
• the tilting of the engraving stylus (15) with respect to the lateral surface (17) is achieved by a correspondingly tilted fastening, for example by gluing, of the engraving stylus (15) in the lever (14) of the engraving member.
• the exact insertion of the engraving stylus (15) into the lever (14) is carried out, for example, by means of a mounting device according to DE-PS 22 13 768.
• the tilting of the engraving stylus (15) is achieved by constructively inclining the longitudinal axis of the rotating system (6, 7, 8, 9) of the engraving member in relation to a reference tangent applied to the lateral surface (17) of the printing cylinder (16).

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Manufacture Or Reproduction Of Printing Formes (AREA)
• Actuator (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=7895336

Family Applications (1)

Country Status (6)

Families Citing this family (4)

Citations (5)

Family Cites Families (5)

• 1999
  • 1999-01-25 DE DE19902884A patent/DE19902884B4/de not_active Expired - Fee Related
  • 1999-11-04 EP EP99963198A patent/EP1150842B1/de not_active Expired - Lifetime
  • 1999-11-04 JP JP2000594643A patent/JP3605364B2/ja not_active Expired - Fee Related
  • 1999-11-04 DE DE59905687T patent/DE59905687D1/de not_active Expired - Lifetime
  • 1999-11-04 WO PCT/DE1999/003521 patent/WO2000043203A1/de active IP Right Grant
  • 1999-11-04 CN CN99815830A patent/CN1109602C/zh not_active Expired - Fee Related
  • 1999-11-04 US US09/889,304 patent/US6736035B1/en not_active Expired - Fee Related

Patent Citations (5)

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